Microscale is the key: microstructural and microchemical studies of metamorphic processes to unravel compositional and geodynamic evolution of the Earth
Most geodynamic processes are controlled by the physico-chemical properties of rocks, which in turn directly depend on the chemical reactions experienced during their metamorphic evolution. Mineralogical and chemical modifications during metamorphism are recorded as textural features, specific mineral assemblages and variations in the chemical composition of phases. However, what can be observed in natural metamorphic rocks is the cumulative result of their entire evolution, in most cases long and complex. Unfolding the contribution of distinct metamorphic processes is thus a challenging task, often complicated by the effects of fluids and post-peak re-equilibration on the mineral assemblage. As mineral reactions and element transport are controlled by micro- and nano-scale processes, microstructural and in-situ microchemical studies are crucial keys for the interpretation of the P-T-X evolution of metamorphic rocks. This session aims to collect and discuss the most recent discoveries in this field, focusing on micro- and nano-scale studies of metamorphic rocks equilibrated under a broad range of conditions, from shallow crust to the ultrahigh pressure. Topics of interest include peculiar mineral inclusions assemblages and metamorphic microstructures of difficult interpretation, zoning of major and trace elements in metamorphic minerals, elemental diffusion and geospeedometry, fluids and metamorphic evolution (both fluid inclusions and metasomatism), stable isotope investigations in metamorphic phases, new quantitative mapping methods and thermodynamic modeling.
Silvio Ferrero, Matthias Konrad-Schmolke and Hafiz Rehman